Aspects of Processing and Analysis of Human Gait Data

Abstract

<p>This thesis is mainly directed towards the developement of new techniques that can be used in the analysis of normal and pathological gaits. The kinematic aspects of human gait are studied, and a new technique for the derivation of spatial trajectories of joints from electrogoniometric measurements is presented. The technique relies on the fact that at any point in time, there is at least one point of either foot in contact with the floor. This point is used as an instantaneous reference from which the positions of the joints are calculated. The procedure is repeated for various points of contact during the walk cycles.</p> <p>The spatial trajectories are used in the study of the kinetics of gait. Forces and moments acting at the joints are computed by considering the equations of motion of the segments of the lower extremity. Rates of energy exchange between the muscles crossing the joints and the segments connected by these joints are estimated, and the total energy expenditure by the leg muscles during swing is obtained. The relation between the speed of walking and energy expenditure by the muscles is studied for normal subjects and hemiplegic patients. The outcome of this study is a new method that can be used in the assessment of normal and pathological gaits.</p> <p>A study of the various electromyographic processing strategies is presented. The different processors are evaluated, and the processor that is most suitable for the analysis of gait is determined. This processor is used on EMG signals from various muscles, and the processed signals are used as inputs to systems whose outputs are the muscle torques at the joints. The transfer-function models of these systems are obtained for the swing phase, and then the same models are used to predict muscle torques and floor-reaction forces during the stance phase.</p>